header {
    position: fixed;
    width: 100%;
    height: 50px;
    background-color: black;
    color: white;
}

.header_style {
    text-align: center;
}

.center {
    padding: 50px 50px;
}

.left_content {
    position: fixed;
    width: 150px;
    border-right: 1px gainsboro solid;
    top: 50px;
    margin-bottom: 50px;
    height: 100%;
}

.center_content {
    margin-left: 150px;
    bottom: 50px;
}

footer {
    position: fixed;
    bottom: 0;
    width: 100%;
    height: 50px;
    background-color: black;
    color: white;
}

.footer_style {
    text-align: center;
}